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Noisy Roof A/C

August 16, 2021, 07:11:42 am

Roof A/C (Duo-Therm) unit is quiet when if first comes on, but after a while becomes quite noisy. I went up and pulled the cover off and took a video of where the noise is coming from.
https://youtu.be/ZM-yBh0Zwc0

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Re: Noisy Roof A/C

Reply #1 – August 16, 2021, 08:38:32 am

Right now I have limited internet access so I can't watch the video. Looks like your compressor. I just added additional vibration isolation under the mounting bracket. It looked easier than replacing the existing rubber mounts.  A couple of them were hard to get to without disconnecting the plumbing.  Loosened the bolts, slid the material under and retighten the bolts.

The additional material significantly reduced the pounding noise when the compressor kicks in.

Rich

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Re: Noisy Roof A/C

Reply #2 – August 16, 2021, 08:28:52 pm

When listing to it I can't be sure but I just changed the rear fan motor mounts on my coach
and the old ones made a lot of noise. The way to find out if they are gone is to
lift the motor and if the motor lifts up that could be your problem.

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Re: Noisy Roof A/C

Reply #3 – August 17, 2021, 01:07:22 pm

Just was able to watch the video.  That is very loud.

Can you move the compressor and get the sound to stop/lessen?  Maybe pry with a big screwdriver under the compressor mount.  If so, more vibration dampening material will probably help.  If the noise is internal to the compressor, you may need a new A/C to fix the problem.

Rich

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Re: Noisy Roof A/C

Reply #4 – August 17, 2021, 05:41:42 pm

Old Guy,

Where did you get your motor mounts?  I am having the same issue.  My motor mounts from the side with rubber grommets, looks like grommets are worn out.

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Re: Noisy Roof A/C

Reply #5 – August 17, 2021, 08:29:19 pm

Dometic 3310725001 SERVICE KIT, F/MOTOR, Heating, Ventilation & Air Condition...

This is what I got. I googled Dometic parts and I found these threw Amazon.ca and you should be able to
get them threw Amazon.com  There are 4 for each AC but I only had to change the rear ones in both ACs.
So I only bought one set.

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Re: Noisy Roof A/C

Reply #6 – August 18, 2021, 02:00:49 pm

Thank you, that's exactly what I've been looking for!

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